Layering space and time

Ƥǿşŧḗḓ ƀẏ: klilley 4 years, 6 months ȧɠǿ

One of the great advantages of using a Geographical Information System (GIS) in mapping urban landscapes is that it allows us to layer space and time, to see how towns and cities have changed over time.

This can be done by using historic maps produced at certain times in the past, and overlaying these onto modern maps and aerial photographs. This technique is fine for mapping modern landscape changes as more and more maps were produced after 1600, but what about earlier periods, such during as the Middle Ages when fewer maps of towns and cities were made?

Here our project's new maps of medieval Swansea are key. These are modern reconstructions of the medieval urban landscape, and because they are drawn to today's cartographic standards we can use them to show what medieval towns and cities looked like for certain periods in the Middle Ages - as Gareth demonstrates in his blog post.

As well as work on Swansea, a similar GIS exercise has been carried out recently for (London)Derry - UK City of Culture for 2013 - through collaboration between Queen's University Belfast, Derry City Council, and the Royal Irish Academy. For this work a 'web-GIS' is used to layer space and time using historic and historical maps: see

We've used ArcServer for this and have developed a smartphone (etc) app using some of the content (served via ArcGIS Online), which can be accessed at - so for those with GPS enabled phones it's possible to use the app to plot where you are in the city, as well as view the historic maps in real time/space, for example while walking around the city.